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Diffstat (limited to 'drivers/mtd/nand/raw/jz4780_bch.c')
-rw-r--r--drivers/mtd/nand/raw/jz4780_bch.c380
1 files changed, 380 insertions, 0 deletions
diff --git a/drivers/mtd/nand/raw/jz4780_bch.c b/drivers/mtd/nand/raw/jz4780_bch.c
new file mode 100644
index 0000000..731c605
--- /dev/null
+++ b/drivers/mtd/nand/raw/jz4780_bch.c
@@ -0,0 +1,380 @@
+/*
+ * JZ4780 BCH controller
+ *
+ * Copyright (c) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include "jz4780_bch.h"
+
+#define BCH_BHCR 0x0
+#define BCH_BHCCR 0x8
+#define BCH_BHCNT 0xc
+#define BCH_BHDR 0x10
+#define BCH_BHPAR0 0x14
+#define BCH_BHERR0 0x84
+#define BCH_BHINT 0x184
+#define BCH_BHINTES 0x188
+#define BCH_BHINTEC 0x18c
+#define BCH_BHINTE 0x190
+
+#define BCH_BHCR_BSEL_SHIFT 4
+#define BCH_BHCR_BSEL_MASK (0x7f << BCH_BHCR_BSEL_SHIFT)
+#define BCH_BHCR_ENCE BIT(2)
+#define BCH_BHCR_INIT BIT(1)
+#define BCH_BHCR_BCHE BIT(0)
+
+#define BCH_BHCNT_PARITYSIZE_SHIFT 16
+#define BCH_BHCNT_PARITYSIZE_MASK (0x7f << BCH_BHCNT_PARITYSIZE_SHIFT)
+#define BCH_BHCNT_BLOCKSIZE_SHIFT 0
+#define BCH_BHCNT_BLOCKSIZE_MASK (0x7ff << BCH_BHCNT_BLOCKSIZE_SHIFT)
+
+#define BCH_BHERR_MASK_SHIFT 16
+#define BCH_BHERR_MASK_MASK (0xffff << BCH_BHERR_MASK_SHIFT)
+#define BCH_BHERR_INDEX_SHIFT 0
+#define BCH_BHERR_INDEX_MASK (0x7ff << BCH_BHERR_INDEX_SHIFT)
+
+#define BCH_BHINT_ERRC_SHIFT 24
+#define BCH_BHINT_ERRC_MASK (0x7f << BCH_BHINT_ERRC_SHIFT)
+#define BCH_BHINT_TERRC_SHIFT 16
+#define BCH_BHINT_TERRC_MASK (0x7f << BCH_BHINT_TERRC_SHIFT)
+#define BCH_BHINT_DECF BIT(3)
+#define BCH_BHINT_ENCF BIT(2)
+#define BCH_BHINT_UNCOR BIT(1)
+#define BCH_BHINT_ERR BIT(0)
+
+#define BCH_CLK_RATE (200 * 1000 * 1000)
+
+/* Timeout for BCH calculation/correction. */
+#define BCH_TIMEOUT_US 100000
+
+struct jz4780_bch {
+ struct device *dev;
+ void __iomem *base;
+ struct clk *clk;
+ struct mutex lock;
+};
+
+static void jz4780_bch_init(struct jz4780_bch *bch,
+ struct jz4780_bch_params *params, bool encode)
+{
+ u32 reg;
+
+ /* Clear interrupt status. */
+ writel(readl(bch->base + BCH_BHINT), bch->base + BCH_BHINT);
+
+ /* Set up BCH count register. */
+ reg = params->size << BCH_BHCNT_BLOCKSIZE_SHIFT;
+ reg |= params->bytes << BCH_BHCNT_PARITYSIZE_SHIFT;
+ writel(reg, bch->base + BCH_BHCNT);
+
+ /* Initialise and enable BCH. */
+ reg = BCH_BHCR_BCHE | BCH_BHCR_INIT;
+ reg |= params->strength << BCH_BHCR_BSEL_SHIFT;
+ if (encode)
+ reg |= BCH_BHCR_ENCE;
+ writel(reg, bch->base + BCH_BHCR);
+}
+
+static void jz4780_bch_disable(struct jz4780_bch *bch)
+{
+ writel(readl(bch->base + BCH_BHINT), bch->base + BCH_BHINT);
+ writel(BCH_BHCR_BCHE, bch->base + BCH_BHCCR);
+}
+
+static void jz4780_bch_write_data(struct jz4780_bch *bch, const void *buf,
+ size_t size)
+{
+ size_t size32 = size / sizeof(u32);
+ size_t size8 = size % sizeof(u32);
+ const u32 *src32;
+ const u8 *src8;
+
+ src32 = (const u32 *)buf;
+ while (size32--)
+ writel(*src32++, bch->base + BCH_BHDR);
+
+ src8 = (const u8 *)src32;
+ while (size8--)
+ writeb(*src8++, bch->base + BCH_BHDR);
+}
+
+static void jz4780_bch_read_parity(struct jz4780_bch *bch, void *buf,
+ size_t size)
+{
+ size_t size32 = size / sizeof(u32);
+ size_t size8 = size % sizeof(u32);
+ u32 *dest32;
+ u8 *dest8;
+ u32 val, offset = 0;
+
+ dest32 = (u32 *)buf;
+ while (size32--) {
+ *dest32++ = readl(bch->base + BCH_BHPAR0 + offset);
+ offset += sizeof(u32);
+ }
+
+ dest8 = (u8 *)dest32;
+ val = readl(bch->base + BCH_BHPAR0 + offset);
+ switch (size8) {
+ case 3:
+ dest8[2] = (val >> 16) & 0xff;
+ case 2:
+ dest8[1] = (val >> 8) & 0xff;
+ case 1:
+ dest8[0] = val & 0xff;
+ break;
+ }
+}
+
+static bool jz4780_bch_wait_complete(struct jz4780_bch *bch, unsigned int irq,
+ u32 *status)
+{
+ u32 reg;
+ int ret;
+
+ /*
+ * While we could use interrupts here and sleep until the operation
+ * completes, the controller works fairly quickly (usually a few
+ * microseconds) and so the overhead of sleeping until we get an
+ * interrupt quite noticeably decreases performance.
+ */
+ ret = readl_poll_timeout(bch->base + BCH_BHINT, reg,
+ (reg & irq) == irq, 0, BCH_TIMEOUT_US);
+ if (ret)
+ return false;
+
+ if (status)
+ *status = reg;
+
+ writel(reg, bch->base + BCH_BHINT);
+ return true;
+}
+
+/**
+ * jz4780_bch_calculate() - calculate ECC for a data buffer
+ * @bch: BCH device.
+ * @params: BCH parameters.
+ * @buf: input buffer with raw data.
+ * @ecc_code: output buffer with ECC.
+ *
+ * Return: 0 on success, -ETIMEDOUT if timed out while waiting for BCH
+ * controller.
+ */
+int jz4780_bch_calculate(struct jz4780_bch *bch, struct jz4780_bch_params *params,
+ const u8 *buf, u8 *ecc_code)
+{
+ int ret = 0;
+
+ mutex_lock(&bch->lock);
+ jz4780_bch_init(bch, params, true);
+ jz4780_bch_write_data(bch, buf, params->size);
+
+ if (jz4780_bch_wait_complete(bch, BCH_BHINT_ENCF, NULL)) {
+ jz4780_bch_read_parity(bch, ecc_code, params->bytes);
+ } else {
+ dev_err(bch->dev, "timed out while calculating ECC\n");
+ ret = -ETIMEDOUT;
+ }
+
+ jz4780_bch_disable(bch);
+ mutex_unlock(&bch->lock);
+ return ret;
+}
+EXPORT_SYMBOL(jz4780_bch_calculate);
+
+/**
+ * jz4780_bch_correct() - detect and correct bit errors
+ * @bch: BCH device.
+ * @params: BCH parameters.
+ * @buf: raw data read from the chip.
+ * @ecc_code: ECC read from the chip.
+ *
+ * Given the raw data and the ECC read from the NAND device, detects and
+ * corrects errors in the data.
+ *
+ * Return: the number of bit errors corrected, -EBADMSG if there are too many
+ * errors to correct or -ETIMEDOUT if we timed out waiting for the controller.
+ */
+int jz4780_bch_correct(struct jz4780_bch *bch, struct jz4780_bch_params *params,
+ u8 *buf, u8 *ecc_code)
+{
+ u32 reg, mask, index;
+ int i, ret, count;
+
+ mutex_lock(&bch->lock);
+
+ jz4780_bch_init(bch, params, false);
+ jz4780_bch_write_data(bch, buf, params->size);
+ jz4780_bch_write_data(bch, ecc_code, params->bytes);
+
+ if (!jz4780_bch_wait_complete(bch, BCH_BHINT_DECF, &reg)) {
+ dev_err(bch->dev, "timed out while correcting data\n");
+ ret = -ETIMEDOUT;
+ goto out;
+ }
+
+ if (reg & BCH_BHINT_UNCOR) {
+ dev_warn(bch->dev, "uncorrectable ECC error\n");
+ ret = -EBADMSG;
+ goto out;
+ }
+
+ /* Correct any detected errors. */
+ if (reg & BCH_BHINT_ERR) {
+ count = (reg & BCH_BHINT_ERRC_MASK) >> BCH_BHINT_ERRC_SHIFT;
+ ret = (reg & BCH_BHINT_TERRC_MASK) >> BCH_BHINT_TERRC_SHIFT;
+
+ for (i = 0; i < count; i++) {
+ reg = readl(bch->base + BCH_BHERR0 + (i * 4));
+ mask = (reg & BCH_BHERR_MASK_MASK) >>
+ BCH_BHERR_MASK_SHIFT;
+ index = (reg & BCH_BHERR_INDEX_MASK) >>
+ BCH_BHERR_INDEX_SHIFT;
+ buf[(index * 2) + 0] ^= mask;
+ buf[(index * 2) + 1] ^= mask >> 8;
+ }
+ } else {
+ ret = 0;
+ }
+
+out:
+ jz4780_bch_disable(bch);
+ mutex_unlock(&bch->lock);
+ return ret;
+}
+EXPORT_SYMBOL(jz4780_bch_correct);
+
+/**
+ * jz4780_bch_get() - get the BCH controller device
+ * @np: BCH device tree node.
+ *
+ * Gets the BCH controller device from the specified device tree node. The
+ * device must be released with jz4780_bch_release() when it is no longer being
+ * used.
+ *
+ * Return: a pointer to jz4780_bch, errors are encoded into the pointer.
+ * PTR_ERR(-EPROBE_DEFER) if the device hasn't been initialised yet.
+ */
+static struct jz4780_bch *jz4780_bch_get(struct device_node *np)
+{
+ struct platform_device *pdev;
+ struct jz4780_bch *bch;
+
+ pdev = of_find_device_by_node(np);
+ if (!pdev || !platform_get_drvdata(pdev))
+ return ERR_PTR(-EPROBE_DEFER);
+
+ get_device(&pdev->dev);
+
+ bch = platform_get_drvdata(pdev);
+ clk_prepare_enable(bch->clk);
+
+ return bch;
+}
+
+/**
+ * of_jz4780_bch_get() - get the BCH controller from a DT node
+ * @of_node: the node that contains a bch-controller property.
+ *
+ * Get the bch-controller property from the given device tree
+ * node and pass it to jz4780_bch_get to do the work.
+ *
+ * Return: a pointer to jz4780_bch, errors are encoded into the pointer.
+ * PTR_ERR(-EPROBE_DEFER) if the device hasn't been initialised yet.
+ */
+struct jz4780_bch *of_jz4780_bch_get(struct device_node *of_node)
+{
+ struct jz4780_bch *bch = NULL;
+ struct device_node *np;
+
+ np = of_parse_phandle(of_node, "ingenic,bch-controller", 0);
+
+ if (np) {
+ bch = jz4780_bch_get(np);
+ of_node_put(np);
+ }
+ return bch;
+}
+EXPORT_SYMBOL(of_jz4780_bch_get);
+
+/**
+ * jz4780_bch_release() - release the BCH controller device
+ * @bch: BCH device.
+ */
+void jz4780_bch_release(struct jz4780_bch *bch)
+{
+ clk_disable_unprepare(bch->clk);
+ put_device(bch->dev);
+}
+EXPORT_SYMBOL(jz4780_bch_release);
+
+static int jz4780_bch_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct jz4780_bch *bch;
+ struct resource *res;
+
+ bch = devm_kzalloc(dev, sizeof(*bch), GFP_KERNEL);
+ if (!bch)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ bch->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(bch->base))
+ return PTR_ERR(bch->base);
+
+ jz4780_bch_disable(bch);
+
+ bch->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(bch->clk)) {
+ dev_err(dev, "failed to get clock: %ld\n", PTR_ERR(bch->clk));
+ return PTR_ERR(bch->clk);
+ }
+
+ clk_set_rate(bch->clk, BCH_CLK_RATE);
+
+ mutex_init(&bch->lock);
+
+ bch->dev = dev;
+ platform_set_drvdata(pdev, bch);
+
+ return 0;
+}
+
+static const struct of_device_id jz4780_bch_dt_match[] = {
+ { .compatible = "ingenic,jz4780-bch" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, jz4780_bch_dt_match);
+
+static struct platform_driver jz4780_bch_driver = {
+ .probe = jz4780_bch_probe,
+ .driver = {
+ .name = "jz4780-bch",
+ .of_match_table = of_match_ptr(jz4780_bch_dt_match),
+ },
+};
+module_platform_driver(jz4780_bch_driver);
+
+MODULE_AUTHOR("Alex Smith <alex@alex-smith.me.uk>");
+MODULE_AUTHOR("Harvey Hunt <harveyhuntnexus@gmail.com>");
+MODULE_DESCRIPTION("Ingenic JZ4780 BCH error correction driver");
+MODULE_LICENSE("GPL v2");
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